Increasing knowledge of the genetic and epigenetic changes occurring in cancer cells provides an opportunity to detect, characterize, and monitor tumors by analyzing tumor-related nucleic acid sequences and profiles. These changes can be observed by detecting any of a variety of cancer-related biomarkers. Various molecular diagnostic assays are used to detect these biomarkers and produce valuable information for patients, doctors, clinicians and researchers. So far, these assays primarily have been performed on cancer cells derived from surgically removed tumor tissue or from tissue obtained by biopsy.
However, the ability to perform these tests using a bodily fluid sample is oftentimes more desirable than using a patient tissue sample. A less invasive approach using a bodily fluid sample has wide ranging implications in terms of patient welfare, the ability to conduct longitudinal disease monitoring, and the ability to obtain expression profiles even when tissue cells are not easily accessible, e.g., in the prostate gland. For these samples, the collection methods previously disclosed often required a digital rectal exam (DRE) or prostate massage to enable enough prostate-derived cellular fluid to enter the urine. Samples collected without DRE or prostate massage showed a lower detection rate of these biomarkers.
Accordingly, there exists a need for new, noninvasive methods of detecting biomarkers, for example, biomarkers in urinary microvesicles, to aid in diagnosis, prognosis, monitoring, or therapy selection for a disease or other medical condition of the prostate gland. In particular, there exists a need for noninvasive methods that do not require DRE or prostate massage prior to urine sample collection and do not require a sample preparation step involving isolation of a cellular pellet from urine samples.